diff --git a/backend/tests/Feature/SetsEndpointTest.php b/backend/tests/Feature/SetsEndpointTest.php
index 54a730a..b2afe90 100644
--- a/backend/tests/Feature/SetsEndpointTest.php
+++ b/backend/tests/Feature/SetsEndpointTest.php
@@ -222,6 +222,71 @@ class SetsEndpointTest extends TestCase
         );
     }
 
+    public function testDeleteSetRequiresAuthentication(): void
+    {
+        $setRepository = app(SetRepository::class);
+        $set = $setRepository->create(new CreateSetDto(
+            name: 'Set to delete',
+            description: 'Set deletion description',
+            iconImageUrl: '/assets/delete-icon.png',
+        ));
+
+        $response = $this->deleteJson("/api/sets/{$set->getId()}");
+
+        $response->assertUnauthorized();
+        $response->assertExactJson([
+            'error' => 'unauthenticated',
+        ]);
+    }
+
+    public function testAuthenticatedDeleteSetRemovesSetAndElements(): void
+    {
+        $setRepository = app(SetRepository::class);
+        $elementRepository = app(ElementRepository::class);
+        $this->createSession('valid-token');
+        $set = $setRepository->create(new CreateSetDto(
+            name: 'Set to delete',
+            description: 'Set deletion description',
+            iconImageUrl: 'set-icons/delete-icon.png',
+        ));
+        $rootElement = $elementRepository->create(new CreateElementDto(
+            set: $set,
+            title: 'Root to delete',
+            description: 'Root deletion description',
+            iconImageUrl: 'set-icons/delete-icon.png',
+            richText: '',
+            shortPdfPath: null,
+            longPdfPath: null,
+            youtubeUrl: null,
+            parentElement: null,
+        ));
+        $childElement = $elementRepository->create(new CreateElementDto(
+            set: $set,
+            title: 'Child to delete',
+            description: 'Child deletion description',
+            iconImageUrl: 'element-icons/delete-child.png',
+            richText: '',
+            shortPdfPath: 'element-pdfs/short/delete-child.pdf',
+            longPdfPath: 'element-pdfs/long/delete-child.pdf',
+            youtubeUrl: null,
+            parentElement: $rootElement,
+        ));
+
+        $response = $this->withCredentials()
+            ->withUnencryptedCookie('auth_token', 'valid-token')
+            ->deleteJson("/api/sets/{$set->getId()}");
+
+        $response->assertNoContent();
+        $this->assertNull($setRepository->find($set->getId()));
+        $this->assertNull($elementRepository->find($rootElement->getId()));
+        $this->assertNull($elementRepository->find($childElement->getId()));
+        $setsResponse = $this->getJson('/api/sets');
+        $setsResponse->assertOk();
+        $setsResponse->assertJsonMissing([
+            'id' => $set->getId(),
+        ]);
+    }
+
     public function testCreateSetRequiresIconImage(): void
     {
         $this->createSession('valid-token');
diff --git a/backend/tests/Unit/Set/UseCases/DeleteSetTest.php b/backend/tests/Unit/Set/UseCases/DeleteSetTest.php
new file mode 100644
index 0000000..6c7272f
--- /dev/null
+++ b/backend/tests/Unit/Set/UseCases/DeleteSetTest.php
@@ -0,0 +1,140 @@
+<?php
+
+namespace Tests\Unit\Set\UseCases;
+
+use App\Element\CreateElementDto;
+use App\Element\Element;
+use App\Exceptions\BadRequestException;
+use App\Exceptions\NotFoundException;
+use App\Set\CreateSetDto;
+use App\Set\Set as DomainSet;
+use App\Set\UseCases\DeleteSet\DeleteSet;
+use App\Set\UseCases\DeleteSet\DeleteSetRequest;
+use Tests\Fakes\FakeElementRepository;
+use Tests\Fakes\FakeFilesystem;
+use Tests\Fakes\FakeSetRepository;
+use Tests\TestCase;
+
+class DeleteSetTest extends TestCase
+{
+    private FakeSetRepository $setRepository;
+
+    private FakeElementRepository $elementRepository;
+
+    private FakeFilesystem $filesystem;
+
+    private DeleteSet $deleteSet;
+
+    protected function setUp(): void
+    {
+        $this->setRepository = new FakeSetRepository();
+        $this->elementRepository = new FakeElementRepository();
+        $this->filesystem = new FakeFilesystem();
+        $this->deleteSet = new DeleteSet(
+            $this->setRepository,
+            $this->elementRepository,
+            $this->filesystem,
+        );
+    }
+
+    public function testDeletesSetElementTreeAndManagedFiles(): void
+    {
+        $set = $this->createSet('set-icons/set.png');
+        $rootElement = $this->createElement(
+            set: $set,
+            parentElement: null,
+            title: 'Root',
+            iconImageUrl: 'set-icons/set.png',
+            shortPdfPath: null,
+            longPdfPath: null,
+        );
+        $childElement = $this->createElement(
+            set: $set,
+            parentElement: $rootElement,
+            title: 'Child',
+            iconImageUrl: 'element-icons/child.png',
+            shortPdfPath: 'element-pdfs/short/child.pdf',
+            longPdfPath: 'element-pdfs/long/child.pdf',
+        );
+        $grandchildElement = $this->createElement(
+            set: $set,
+            parentElement: $childElement,
+            title: 'Grandchild',
+            iconImageUrl: 'element-icons/grandchild.png',
+            shortPdfPath: 'element-pdfs/short/grandchild.pdf',
+            longPdfPath: 'element-pdfs/long/grandchild.pdf',
+        );
+
+        $this->deleteSet->execute(new DeleteSetRequest(id: $set->getId()));
+
+        $this->assertNull($this->setRepository->find($set->getId()));
+        $this->assertNull(
+            $this->elementRepository->find($rootElement->getId()),
+        );
+        $this->assertNull(
+            $this->elementRepository->find($childElement->getId()),
+        );
+        $this->assertNull(
+            $this->elementRepository->find($grandchildElement->getId()),
+        );
+        $this->assertEqualsCanonicalizing([
+            'set-icons/set.png',
+            'element-icons/child.png',
+            'element-pdfs/short/child.pdf',
+            'element-pdfs/long/child.pdf',
+            'element-icons/grandchild.png',
+            'element-pdfs/short/grandchild.pdf',
+            'element-pdfs/long/grandchild.pdf',
+        ], $this->filesystem->deletedPaths);
+        $this->assertSame(
+            count($this->filesystem->deletedPaths),
+            count(array_unique($this->filesystem->deletedPaths)),
+        );
+    }
+
+    public function testRequiresSetId(): void
+    {
+        $this->expectException(BadRequestException::class);
+        $this->expectExceptionMessage('setId is required');
+
+        $this->deleteSet->execute(new DeleteSetRequest(id: null));
+    }
+
+    public function testThrowsWhenSetIsMissing(): void
+    {
+        $this->expectException(NotFoundException::class);
+        $this->expectExceptionMessage('Set not found');
+
+        $this->deleteSet->execute(new DeleteSetRequest(id: 999));
+    }
+
+    private function createSet(string $iconImageUrl): DomainSet
+    {
+        return $this->setRepository->create(new CreateSetDto(
+            name: 'Set',
+            description: 'Set description',
+            iconImageUrl: $iconImageUrl,
+        ));
+    }
+
+    private function createElement(
+        DomainSet $set,
+        ?Element $parentElement,
+        string $title,
+        ?string $iconImageUrl,
+        ?string $shortPdfPath,
+        ?string $longPdfPath,
+    ): Element {
+        return $this->elementRepository->create(new CreateElementDto(
+            set: $set,
+            title: $title,
+            description: "$title description",
+            iconImageUrl: $iconImageUrl,
+            richText: '',
+            shortPdfPath: $shortPdfPath,
+            longPdfPath: $longPdfPath,
+            youtubeUrl: null,
+            parentElement: $parentElement,
+        ));
+    }
+}